Studies are proposed with which to continue and extend findings relevant to the role of environmental light on the development of photoreceptor cell rod outer segment and pigment epithelial cell membranes in normal rats and those afflicted with hereditary retinal degeneration. The differential susceptibilities of retinal membranes in the two rat strains to light induced oxidative stress will be exploited by comparisons of cyclic light and total dark rearing regimes, light intensity and duration of exposure and the Vitamin A deficient state. The development and interaction of major rod outer segment proteins (rhodopsin) and antioxidative metabolites will be measured with respect to light rearing conditions, age and dietary and genetic background. Mechanisms of oxygen mediated light induced lipid peroxidation will be evaluated from analytical studies of retinal tissue lipid composition and the analysis of polyunsaturated fatty acid oxidative intermediates in tissues and artificial reconstituted vesicles by physical-chemical techniques. A comparison of retinal pigment epithelium cell plasma membrane proteins and lipid composition and their interactions in intact isolated pigment epithelial cells will also be assessed in normal and mutant rats.